Conventional reel-type video slot machines accept the player's bet of credits, initiate the spinning of virtual reels, randomly stop the reels to display a final array of symbols, then grant an award to a player based on the occurrence of winning symbol combinations across paylines and based on the player's initial bet per payline.
It would be more interesting for the player if an additional secondary game were also played. Ideally, the secondary game would have the potential of awarding very high awards, yet would have a high win frequency for lower value awards. The secondary game should also not take too much time to play and be simple to understand.